I'd like to attach my comments to a concerned friend along with links to others' posts that addressed this concern far better than I could.
I agree with your concern over what is happening in Texas. What the social services did has serious consequences for every family in this country if left unchecked. I agree with you that the potential is very frightening! I was extremely relieved when the court ordered them to return the children. If there was a concern about a particular child being abused or was coerced or whatever, then the social services department should have had more evidence of a legal violation (that would hold up in court)---not that they didn't like the religion. That infringes on the freedom of religion that we hold dear. The method that they used was despicable, in my opinion, and caused far more fear in the children than they had ever known and should have ever known. That's just wrong.
As to Mormons and polygamy, I need to first make sure you understand that the FLDS Church has no connection to the LDS Church, commonly called the Mormons. Polygamy has not been practiced in our church for over a hundred years and coercion was never part of the LDS Church polygamists' lives. Children and wives were well cared for, and each usually had their own homes/farms. I am a product of polygamy on multiple sides, and I am satisfied that there was no coercion in any case and the children were prized and cared for as children should be. I believe the first wife had to agree to polygamous marriages. Sometimes it was a way to provide for a widow. I had one great grandmother whose husband died, and he requested a friend to take her as his polygamist wife and care for her. It is interesting to note that only a small percentage of members actually practiced polygamy and the men were respected as upright men.
Here is a post of a blogger I follow. In that post, she links to another writer who explains the differences between the two churches even more. If you're interested, my father-in-law wrote a post at http://www.rnsmith.com/?p=1110 about this situation as well. He cites the LDS (my church's) statement regarding it. These links are some of the best I have found to date, and I would seriously urge you to read them. I learned some things I hadn't known, specifically as it related to the FLDS church.
That was the long answer. The short answer is that I was incredibly relieved when the court ordered the children returned to their mothers.